...this is another problem, that doesn't invalidate const itself. Const applies to a specific...

...defining a tmp
reference), because it will invalidate the tmp reference, not the
actual one...

...so that a copying GC doesn't invalidate the pointer held by the foreign code...

...That's bad - a compiler upgrade would invalidate all objs and libs, and that can...

...the case where a folder is moved to itself. It would invalidate the invariant.

L.

...new ObviousProblem();
  o.data.invalidate();

  SubtleProblem  s =  new SubtleProblem();
  s.invalidate();

In short extending a...

...Other values in various positions can also invalidate a sequence. 0xC0, 0xC1, 0xF5 and 0xFF...

...won't matter, but it doesn't invalidate the point)

The second point pro a...

...function call.

What about parameter default values?
#void Invalidate( enum{no_redraw,redraw} =redraw );

L.

...the names of function parameters when calling:

Invalidate(redraw : true);

There were probably some reasons...